Background: For a few years now there is significant difference in the calculation of the cosmological constant between standard candles methods and CMB methods. CMB measurement comes from a very young universe (~400k years) and the resulting cosmological constant as calculated by the Planck collaboration is smaller than what is observed today.
Question: Is this so-called "tension" the main reason for talking about accelerated expansion?
I've found a relevant article by Hossenfelder. I understand that according to the article, the answer to this question is "yes; but we've also seen some other minor indications in support of accelerated expansion".
Note: The question is not about whether any of the measurements are plagued by uncertainties or how trustworthy they are in general.